Ultra short wave oscillation generator



June 2, 1936.

D. PRINZ ET AL.

ULTRA SHORT WAVE OSGILLATION GENERATOR Filed June 14, 1933 INVENTOR 0057/9/67! P/W/VZ ATTORNEY s ren STATES PATENT OFFICE ULTRA SHORT WAVE OSCILLATION GENERATOR Dietrich Prinz and Hans Otto Roosenstein, Berlin, Germany, assignors to Telefunken Gesell-' schaft fiir Drahtlose Telegraphic m. b. H., Berlin, Germany, a corporation of Germany Application June 14, 1933, Serial No. 675,680 In Germany June 28, 1932' 6 Claims. (Cl. 250-36) The present invention relates to thermionic feed-back equation shows that, as a consequence, oscillation generators for the production of exthe production of oscillations would still be feasitremely high frequencies, and particularly to such ble in the presence of frequencies for which the generators of the screen grid type. low impedance of the oscillation circuit would In the majority of circuit arrangements for entirely preclude all chances of exciting oscillathe production of short waves, the use of screen tions in normal tubes. grid tubes is attended with difiiculties due to the In other words, the invention consists, in the fact that the screen grid is in radio frequency first place, in the use of screen grid tubes in exconnection with the cathode and tends to intremely high frequency oscillation generator cir- 10 crease the grid-filament and the plate-filament cuit arrangements of the sort above described; 10

capacitance. Asa consequence there is a shift and secondly, in choosing proportions and diin the frequency to which the grid and the plate mensions whereby the direct grid and plate cacircuits are naturally resonant. Circuit arrangepacitance of the tube is reduced to a minimum ments may be provided, however, wherein the value. Such dimensioning is determined from length of the generated wave is merely a function the consideration that, in a normal tube, the op- 15,

of the resultant grid plate capacitance, i. e., of timum grid-plate alternating voltage for maxithe composite capacity due to the series arrangemum efliciency presents a phase difference of ment of the grid filament and the plate filament 180 degrees so that between the grid and the capacitances, and the grid plate capacitance arplate there exists a region or plane of constant ranged in parallel thereto. This latter capacipotential. Mounting in this surface a metallic 20 tanee in circuit arrangements of this kind should wire network which is connected with the oathas far as possible be minimized. The capacities ode, it will be seen that this will evidently not of the partof the oscillation circuit located excause any alteration at all in the distribution of ternally of the tube between grid and filament, the radio frequency potentials, nor in the gridand between filament and plate, are to be underplate capacitance. Now, according to this in- 25 stood as being included in the grid-filament cavention, the screen grid is placed in the region pacitance and the filament-plate capacitance. which is at constant potential.

A circuit scheme in which the wave length de- It will be readily understood that in a tube of pends solely upon the resultant grid-plate cathe said kind the capacity Csa between the screen pacitance as above defined, will be obtained, for grid and the plate is to the capacity Cgs between 0 instance, by associating the grid with the plate the control grid and the screen grid as the optiby means of the coil contained in the oscillation mum control grid alternating voltage Eg is to circuit, the feed-back being obtained by the inthe optimum plate alternating voltage Ea, thus:

'ternal tube capacitances. The sole figure of the C E drawing shows a circuit scheme of this sort. Re- 35 ferring to this figure, condenser I serves here merely as a block condenser in that it is used for What follows therefrom for a cylindrical arthe purpose of precluding the plate D. C. voltage rangement is from becoming active at the grid. 2 and 3 de- 40 note choke coils for the supply of grid and plate E 40 D. C. voltage. I 7

Now, when screen grid tubes are used in a circuit scheme such as that which has just now been discussed, the resultant grid-plate capacity need Where Ta, Ts, and 's are th radli 0f the P at the not be essentially higher than would be the case Screen grid, a d t grid a d Zn es at s the 45 if there were no screen grid. In fact the grid natural logarithm In the a f a p ane-parand m t might have t same dimensions as allel form of construction there holds good would be preferred in a, tube of the triode type. E d It is possible, therefore, to tune such a circuit to as short a wave length when employing a screen grid tube as would be possible using a triwhere dsa, the distance intervening between the ode tube. The gain reciprocal, however, may be screen grid and the plate, and dgs is the distance substantially lower, although the feed-back facbetween the control grid and screen grid. tor is not less than in a standard triode tube of We claim: the same dimensions. An examination of the 1. An oscillation generator circuit for the pro- 5 duction of extremely high frequencies comprising an electron discharge device having an anode, cathode, control'electrcde, and screen electrode, an oscillatory circuit between said anode and control electrode, said screen electrode being located at a point of substantially constant alternating potential between said anode and cathode.

2. An oscillation generator circuit for the production of extremely high frequencies comprising an electron discharge device having an anode, cathode, control electrode, and screen electrode, and an inductance between said anode and control electrode, the oscillatory circuit of said generator comprising said inductance and the internal capacity of said device, means for maintaining said screen at a positive potential relative to said cathode, said screen being positioned in said device at a location which, as regards alternating voltage, is substantially at cathode potential.

3. An oscillation generator circuit for the production of extremely high frequencies comprising an electron discharge device having an anode, cathode, control electrode, and screen electrode, an oscillatory circuit between said anode and control electrode, the dimensions of said electrodes being such that the ratio between the screen to anode capacitance and the screen to control electrode capacitance corresponds substantially to the ratio between the optimum alternating voltages of the control electrode and anode.

l. An oscillation generator circuit for the production of extremely high frequencies comprising an electron discharge device having an anode, cathode, control electrode, and screen electrode, an oscillatory circuit between said anode and control electrode, said anode, screen and control electrodes being of cylindrical form, the dimensions being such that the logarithm of diameter ratio of anode and screen electrode is related to the logarithm of the diameter ratio of screen and control electrode substantially as the optimum anode alternating potential and optimum control electrode alternating voltage.

5. An oscillation generator circuit for the production of extremely high frequencies comprising an electron discharge device having an anode, cathode, control electrode, and screen electrode, an oscillatory circuit between said anode and control electrode, said anode, screen and control electrodes being located in different parallel planes, the dimensions being such that the ratio of the distance between the screen and the anode to the space intervening between the control electrode and the screen is substantially equal to the ratio between the optimum anode alternating voltage and the optimum control electrode alternating voltage.

6. An oscillation circuit comprising an electron discharge device on whose anode and grid are voltages the phases of which are in opposition whereby the alternating potential at some point between the anode and grid is zero, and. a screen grid located between said anode and grid at said zero point.

DIETRICH PRINZ. HANS OTTO ROOSENSTEIN. 

